It is known that alkyl polyglycosides exhibit significantly higher foaming profiles than other nonionic surfactants, such as alcohol ethoxylates. In fact, it can be said that the foaming tendencies of alkyl polyglycosides more closely resemble those of anionic surfactants, such as alcohol sulfates, than the foaming tendencies of other nonionic surfactants. This higher foaming tendency makes the use of alkyl polyglycosides undesireable for many applications, e.g. cleaning-in-place for food processing plants, high pressure spray cleaning, bottle washing, floor cleaners and automatic dishwashing, wherein high levels of foam interfere with the cleaning and rinsing operation and reduce the efficiency of the operation.
Low foam nonionics, such as EO/PO block copolymers, can be used to reduce the foaming properties of alkyl polyglycoside surfactants, but these materials have undesireable properties, e.g. low biodegradability, relatively high aquatic toxicity and poor caustic compatability.
Accordingly, there is a need for the development of methods for decreasing the foaming tendency of alkyl polyglycoside containing compositions without simultaneously affecting the beneficial properties of the alkyl polyglycosides, e.g. good cleaning ability, high biodegradability, low aquatic toxicity and good caustic compatability.